Inconsistent merge on subdirectory behavior?

I wanted to reverse-merge some accidental changes on a subdirectory on my branch and svn really confuses me in this. Is the below behavior from subversion intended or have I stubled on a bug?

I wanted to reverse-merge revision 1000 on all the files in the directory "sub/dir", below illustrated with only one file.

wcroot> svn diff --summarize -c 1000 sub/dir
M sub/dir/foobar.txt
wcroot> svn merge -c -1000 sub/dir
--- Recording mergeinfo for reverse merge of r1000 into '.':
 U .
So the file sub/dir/foobar.txt is not reverse-merged (and the merge info is elided even though the output does not say so)

I tried a few different versions of this with e.g. -r 1000:999 with identical results.

Then I did the following, which I thought would be more of the same:

wcroot> cd foo/bar
wcroot/foo/bar> svn merge -c -1000 .
--- Reverse-merging r1000 into '.':
U sub/dir/foobar.txt
--- Recording mergeinfo for reverse merge of r1000 into '.':
 G .
--- Eliding mergeinfo from '.':
 U .

So now it does what I wanted to.

Is it intended that merge should do different things if I use "." or "sub/dir" as my WCTARGET? I find it confusing and it was mostly luck that I stumbled on the right solution. "svn help merge" does not seem to indicate that these two use cases should be any different, but I may misread it.
Btw, this was done with "svn, version 1.9.5 (r1770682)"

TIA,
  Chris
Received on 2018-04-11 16:57:10 CEST